I guess there is not a 1911 shooter on this planet (or actually any pistol shooter), who is not aware of the fact that our beloved toys rely onto springs, to function correctly. Recoil spring, firing pin spring, main spring, sear spring etc. Any 1911 shooter who cares for his pistol will tell you, that he replaces his pistol's springs (at least the recoil spring and the firing pin spring), on a regular basis. The reason is that the springs loose their effectiveness after a certain number of rounds are fired. One other thing that most 1911 shooters have noticed, is that even a new spring, when installed in a pistol looses some of its free length, after a very short time. These things always puzzled me, and I always wondered why. Why a new spring looses 1/2" of free length one month after I install it in my gun.

Well, obviously the springs tend to loose some of their length because they remain compressed inside the pistol. The additional burden of being fully compressed whenever you fire the pistol takes its toll as well, hense the loss of length.

Here is a company, which is making some interesting promises about the prings it produces. How would you like a recoil spring which is guaranteed not to loose more than 0.375” of free length in 12 months regardless of the number of rounds fired? This company is Integrated Systems Management Inc., or ISMI for short.

Here is some info from ISMI's site

ISMI premium springs are manufactured exclusively with certified aerospace specification alloys; stainless or chrome silicon. Then our springs are heat treated, shot peened and stress relieved after winding to enhance performance and durability. Our springs utilize the same design and manufacturing technology as used in IndyCar and Formula One racing. In a typical 500 mile race, a valve spring in an IndyCar will go through more than 2,500,000 compression cycles. Consideration of factors such as modulus, wire diameter, mean diameter, active coils, total deflection, spring relaxation, maximum service temperature, and operating environment; results in you having modern spring technology available for your pistol.

Because of the properties of music wire; it cannot be heat treated, shot peened and stress relieved after the spring is wound. Additionally, music wire lacks consistency from bulk lot to bulk lot. This results in inconsistent performance from spring to spring. This is the same technology that was in use 90 years ago when John Browning designed the 1911 style pistol.

We believe that springs shouldn’t be an ongoing worry or concern for the shooter. Springs should be an annual routine maintenance item. Change them once a year; go shoot and have fun.

We believe our products are “The World’s Finest Gun Springs”. It is this belief that allows us to offer a replacement warranty that is unmatched. We acknowledge that anything that can be produced may have a problem. This is why we offer the warranty. As a consumer, you would not consider buying a new car, computer, appliance or other item with no warranty, you gun springs should be the same. If they are good enough to sell, they are good enough to stand behind.

ISMI springs come in various ratings, starting from the 20 lbs all the way down to 7 lbs, so I am sure you can find one matching your shooting loads. Their mainsprings come in either 15, 17 or 19 lbs and made either stainless alloy or Chrome Silicon steel. Finally, they offer several magazine springs for either 8 round, 10 round or Officer's size mags.

Around September 2003, ISMI were kind enough to send me some of their springs for testing.

As soon as I received them, I removed the recoil spring from my .45 1911 and replaced it with an 18 lbs ISMI chrome silicon one. In the picture below, you can see the removed spring next to a brand new ISMI spring. Obviously, the removed spring has lost more than 1/2" of standing length.

The new ISMI spring was installed in my pistol on October 28th, 2003. Since then, it has lost only .2 cm (2 mm) of its free length. In other words, during those seven months, with a few hundrend shots fired, the ISMI spring has lost only .08" of standing length!!

I've measured its length at installation and it was exactly 17 cm. As it is today, its length is 16.8 cm, an amazing loss of only 2 mm!!

I guess this is quite a good performance, considering that the spring I removed from my pistol, and which has been in it for around four months, had lost more than .5", with the same amount of rounds fired through the pistol. As far as I am concerned, ISMI springs have won a place inside all my pistols.

If you are interested in some more reading, here is a link to ISMI's FAQ page.


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